fix(v2/log): Replace panic with slog.Default() fallback in FromContext

Vasilii Iakliushinrequested to merge
from-context-fallback-to-slog-default into master

What does this MR do and why?

Problem

log.FromContext panics when called on a context that hasn't been seeded with a logger via WithLogger. This forces every consumer — including every test file — to defensively seed contexts before any code path that touches logging. In gitlab-shell alone, the labkit/v2 migration required adding boilerplate in 11+ test call sites across 6 files.

Solution

Return slog.Default() when no logger is found in context, following the precedent set by commit 4922f016 which replaced a panic with a graceful New() fallback in WithFields for the same safety reasons. The standard library's slog package itself follows this philosophy.

References

  • Commit 4922f016 — prior precedent for replacing panic with graceful fallback in v2/log

Screenshots or screen recordings

Not applicable — no UI changes.

How to set up and validate locally

  1. cd v2 && go test ./log/...
  2. Verify all tests pass, including the updated TestFromContext/returns_slog.Default_when_logger_not_in_context test.

MR acceptance checklist

Evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Merge request reports